Good evening, I have a general question regarding the 4wd system. I know it's a part time system and that it should not be engaged unless on slippery surfaces. However when you do engage 4wd (lo or hi), my understanding is that all 4 wheels are LOCKED, I.e. they will rotate at the same speed, hence the scrubbing you get if you do engage on Tarmac. This guaranteed rotation is what will pull you free providing at least 1 wheel has traction of course. If this is true, why is it then that I have seen videos of Navs stuck in the mud with only 1 wheel spinning, the other 3 wheels stationery? He must have been in 4wd as it was the front wheel that was spinning. Thanks in advance.
pussernav
Unless the axles themselves have locking diffs, or traction control ( which most Navaras do not have ), it is possible to have a wheel on each axle spin.
The reason you get transmission wind up on sealed surfaces is the front axle tends to travel further than the rear.
The reason you get transmission wind up on sealed surfaces is the front axle tends to travel further than the rear.
When you put the truck in 4x4 it does NOT lock the axle diffs. However the rear axle does have an lsd or optional locking diff.
Therefore you could easily see a stuation with a front wheel stationary and the other 3 spinning.
HTH
Therefore you could easily see a stuation with a front wheel stationary and the other 3 spinning.
HTH
No, they are not locked, the only standard vehicles fitted with diff locks were the Merc G wagon and the pinzgauer. Most other 4x4 vehicles get by fine with open differentials.
You'll get a full explanation here;
viewtopic.php?f=45&t=1098
You'll get a full explanation here;
viewtopic.php?f=45&t=1098
Thanks all for your replies. As I said earlier, very happy as to when to use the 4wd system, even low range. I've had some very successful off road trips and snowy road conditions. As the advice says, take it slowly and engage 2wd as soon as possible. I still don't properly understand the system though. I have seen the link posted before but read it again anyway, and I do understand that if 4wd was engaged on Tarmac, the front wheels would have too much grip which would not allow the wheels to slip (different speed to the rear...), causing serious damage...eventually. This surely means then that all 4 wheels are rotating at exactly the same speed. How then could you get 1 wheel on an axle spinning whilst the other is stopped. Sorry to sound dumb, and this isn't something that is causing me a problem, just intrigued. It's a great truck, never been stuck, always felt very secure and sure footed off road so certainly not complaining. Thanks again guys.
When you engage 4wd, the only difference is the drive from he main gearbox is split 50/50 to the front and rear axles.
The axles themselves still have fully operational differentials which means that the torque will divert to the wheel with least grip/resistance. As previously mentioned not UK D40s have a 'limited slip' differential on the rear axle and this will resist the urge to allow all the torque to just one wheel.
I'm off for a lie down now :faint
The axles themselves still have fully operational differentials which means that the torque will divert to the wheel with least grip/resistance. As previously mentioned not UK D40s have a 'limited slip' differential on the rear axle and this will resist the urge to allow all the torque to just one wheel.
I'm off for a lie down now :faint
This is not the easiest thing to completely understand. You need to know how a diff functions and understand that all four wheels turn at different speeds while cornering.
Have a read through the wiki articles and web sites such as this http://auto.howstuffworks.com/four-wheel-drive.htm
And http://editorial.autos.msn.com/article. ... tid=435017
Then come back on here and explain it to us :bbbump
Have a read through the wiki articles and web sites such as this http://auto.howstuffworks.com/four-wheel-drive.htm
And http://editorial.autos.msn.com/article. ... tid=435017
Then come back on here and explain it to us :bbbump
I thought there was a 'wind up here, but I've worked it out.PCUK said:
You have an imported D40 with a rear diff lock fitted as standard, the same as Carts. When you activate the switch, it only locks up the rear diff, making the rear wheels rotate together at the same speed regardless of the grip the tyres are exerting.
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